Horizontal curvature for ELR NHM4 is based on the digitised notional centre-line, calculated in 100 metre sections. The average radius computation is weighted, however this should be treated as indicative only. The computed minimum and maximum radii are shown for completeness, and often report a much tighter radius than the physical railway. Radii calculations are influenced by the digitisation quality, and often produce inaccurate values at the extremities of the ELR, areas of tracks divergence, and locations of very tight curvature.
| Mileage | Schematic | Average Radius | Radius Range |
|---|---|---|---|
| 18M 0715y - 18M 0770y | ⚪-⚪⚪⚪-⚪ | Straight | Straight |
| 18M 0770y - 18M 0880y | 🟡-🟡🟡🟡-🟡 | Moderate (757 m) | Moderate (757 m) |
| 18M 0880y - 18M 0990y | 🔴-🔴🔴🔴-🟡 | Very Tight (337 m) | Very Tight (231 m) to Moderate (939 m) |
| 18M 0990y - 18M 1100y | ⭕-🔴🔴🔴-🟡 | Very Tight (293 m) | Extremely Tight (177 m) to Moderate (908 m) |
| 18M 1100y - 18M 1210y | 🟠-🟠🟠🟠-🟡 | Moderately Tight (692 m) | Moderately Tight (511 m) to Moderate (939 m) |
| 18M 1210y - 18M 1320y | 🟡-🟡🟡🟡-🟡 | Moderate (785 m) | Moderate (785 m) |
| 18M 1320y - 18M 1430y | 🟠-🟡🟡🟡-🟢 | Moderate (1,133 m) | Moderately Tight (629 m) to Very Flat (10,358 m) |
| 18M 1430y - 18M 1507y | 🟢-🟢🟢🟢-🟢 | Very Flat (5,129 m) | Very Flat (5,129 m) |